The present invention relates to a method of producing earthworm casts using solid fuel ash and an earthworm bed for producing earthworm castings, and more particularly to a method of producing earthworm castings using ash generated from the combustion of solid fuel, the method being able to dispose of the solid fuel ash in an environmentally friendly and economical manner by feeding the solid fuel ash to earthworms to produce earthworm castings, and to an earthworm bed for producing earthworm castings.
Refuse-derived fuels (RDFs; solid fuels) produced from food waste, combustible waste, ocean waste or the like are incinerated to utilize the heat energy. Such solid fuels have a high heating value and are low-priced because they are produced from waste. Moreover, recycling of waste resources for producing the solid fuels results in an economic benefit, and gas generated from the combustion of the solid fuels does not corrode the combustion apparatuses. In addition, a facility for storing the solid fuels does not require a separate safety mechanism. Due to such advantages, the solid fuels are widely used as alternative energy not only in various industrial fields, but also in farming and fishing villages, in order to reduce the use of oil.
An effective method for disposal of ash generated from the combustion of the solid fuels has not yet been developed, and thus the ash is buried in landfills. Thus, the cost for disposal of the ash is required, and environmental pollution is caused by landfilling of the ash. For this reason, technology capable of disposing of the ash is required.
Meanwhile, earthworm castings are excrements of earthworms, which are obtained from the digestion of feed in the digestive tract of the earthworms and contain undegraded fiber residue mixed with viscous materials. Earthworms can produce relatively uniform earthworm castings by mixing even non-uniform feed vertically and in the intestines.
Such earthworm castings have high contents of exchangeable calcium, magnesium, potassium, phosphoric acid and organic matter. In addition, the physical and chemical properties of earthworm castings do not significantly differ between food sources. This is because earthworms use only organic matters having similar humification grades among different feed sources, due to the limited digestive function thereof.
Moreover, earthworm castings are dark brown, do not evolve an unpleasant odor and gas, and contain organic matter, trace elements such as nitrogen, phosphoric acid and potassium, and a large amount of antibiotic Bacillus sp. microorganisms which destroy or dissolve mold harmful to soil to increase the resistance of the soil to blight and harmful insects. Thus, earthworm castings are known as the best natural organic fertilizer.
Hereinafter, the production of fertilizers and earthworm castings will be described.
Korean Patent Laid-Open Publication No. 10-2003-0013054 discloses a method for preparing a compound fertilizer, the method comprising the steps of: mixing 100 parts by weight of a sewage sludge dehydrated cake and 28-59 parts by weight of caustic lime, air-drying and curing the mixture for 3-5 days such that the sewage sludge dehydrated cake has a water content of 3-10%; and mixing 100 parts by weight of the dried sewage sludge with 40-60 parts by weight of stainless steel slag and 5-15 parts by weight of a gallium additive.
Korean Patent Laid-Open Publication No. 10-2005-0088843 discloses a method of producing a fertilizer using sewage sludge, the method comprising: mixing 65-70 wt % of sewage sludge, 5-10 wt % of sawdust, 5-10 wt % of rice bran, 5-10 wt % of a crab shell and 5-10 wt % of zeolite; inoculating seed bacteria, cultured in rice bran, into the mixture in an amount of 1 wt % based on the total amount of the mixture; and fermenting the inoculated mixture in a fermenter at an air supply rate of 200 ml/kg·min to obtain a compost, in which the initial fermentation product is turned over when the temperature thereof decreases to about 30˜50° C. during the fermentation, and is then composted until the temperature thereof no longer changes.
Korean Patent Registration No. 10-0812686 discloses earthworm castings produced by feeding earthworms with sludge from milk processing, and a method for recycling earthworms. It discloses a method in which sludge from milk processing is composted and recycled in a simple and cost-effective manner compared to conventional sludge treatment methods.
Korean Patent Laid-Open Publication No. 10-2010-0026226 discloses a soil amendment comprising 100 parts by weight of an absorbable polymer resin, 30-70 parts by weight of chitosan, 20-40 parts by weight of a fermentation culture obtained by inoculating a medium with at least one strain selected from the group consisting of Bacillus subtilis, Lactobacillus, yeasts and filamentous fungi and culturing the inoculated strain, 20-40 parts by weight of mica, and 20-40 parts by weight of calcium oxide powder.
Hereinafter, earthworm breeding apparatuses for producing earthworm castings will be described.
Korean Patent Laid-Open Publication No. 10-2002-0045871 discloses an apparatus for breeding earthworms using organic waste, comprising: an assembly consisting of an earthworm box, in which earthworms are bred by feeding organic waste, and an earthworm casting box; a storehouse in which the assembly can be received; and a transport means.
Korean Patent Laid-Open Publication No. 10-1998-082831 discloses a method and apparatus of breeding earthworms using food waste and collecting earthworm castings, in which food waste is fed from the top while earthworm castings are collected from the bottom, and earthworm castings, accumulated during the time taken for earthworm eggs to hatch and move, are crushed, discharged and collected, thereby growing earthworms.
Korean Patent Laid-Open Publication No. 10-2000-63722 discloses a grinding device in which an organic raw material stored in a storage tank is finely ground; a separating device in which the material ground in the grinding device is separated according to size and large grains are transferred again to the grinding device; an air blowing device by which the fine organic material separated in the separating device is transferred by blowing air; a drying device in which the organic material transferred by the air blowing device is dried; and a packaging device in which the organic material dried in the drying device is put in a bag having a specific size.
Korean Patent Laid-Open Publication No. 10-2003-0032249 discloses an earthworm breeding apparatus in which an earthworm breeding bed is formed in the shape of a box, such that earthworms can be bred in a three-dimensional multilayer structure and, at the same time, can stably grow, and a surplus of earthworm castings can be easily separated.
Korean Patent Laid-Open Publication No. 10-2004-0006777 discloses an earthworm breeding apparatus for producing earthworm castings, in which earthworms can be bred in a breeding bed in a layered state, whereby the breeding area of the earthworms is maximized and earthworm castings are easily collected using an automated breeding method.
Korean Patent Laid-Open Publication No. 10-2004-0063882 discloses a method for producing earthworm castings, the method comprising: fermenting and aging organic waste such as food waste in a composting process to obtain a fully mature compost; transferring the compost to a band-type earthworm bed having a multistage belt conveyor; breeding earthworms using the transferred compost; sending the bred earthworms to an earthworm separating machine in which mature earthworms are separated; and sending a portion of earthworm castings (for seeding) into the earthworm bed by an earthworm casting return bucket conveyor and sensing the remaining earthworm castings to a packaging process by an earthworm casting transfer conveyor.
Korean Utility Model Registration No. 20-0294434 discloses an earthworm breeding apparatus for producing earthworm castings, in which earthworms can be bred in a breeding bed in a layered state, whereby the breeding area of the earthworms is maximized and earthworm castings are easily collected using an automated method.
Korean Utility Model Registration No. 20-0287400 discloses a device for easily separating earthworms, earthworm eggs and earthworm castings, in which pins capable of separating earthworms are formed to the inside of a cylindrical housing, and holes capable of discharging earthworm castings are formed through the cylindrical housing.
Meanwhile, chitosan can generally be obtained from shells, crab shells and the like. This chitosan can reduce the density of Fusarium fungi in soil, can increase the antiviral activity of plants, can promote the proliferation of useful microorganisms (Actinomycetes, lactic acid bacteria, etc.) in soil, can increase the activity of chitinase from microorganisms, and can kill or inactivate pathogenic microorganisms in soil.